Prefabricated upright wall systems are frequently utilized for dividing large interior spaces into a plurality of smaller spaces such as offices, hallways, conference rooms and the like. Such wall system, where a higher degree of privacy is desired, is frequently of the full-height variety in which the wall panels and the wall defined thereby is about eight to ten feet high. However, the upper edge of the wall is typically spaced downwardly from the building ceiling, with the wall having no significant structural connection to the ceiling other than possible use of small braces which provide solely limited horizontal lateral support. These full-height wall systems typically include doorways for accessing various areas or regions, such as workspaces and conference rooms. To increase privacy, the wall system is frequently provided with a sliding door positioned laterally adjacent one side of the wall and supported from an overhead track secured to the wall for movement between a closed position wherein the door extends across the door opening, and an open position wherein the door is sidewardly displaced from the door opening and laterally overlies one side of an adjacent wall section. Because of the overall construction and manner of support of such wall systems, and specifically the fact that the upper header structures which extend along the wall and across the doorway are spaced downwardly from the ceiling and are free of any direct vertical structural support therewith, and are also readily visible, the overall design and structural characteristics of the header structure, and specifically the header which extends across the doorway and along the associated door support track, have long presented problems with respect to structural design thereof so as to minimize size, weight and overall complexity, particularly with respect to supporting a sliding door, while at the same time providing desired aesthetics. These design problems become of greater significance in wall systems wherein the wall panels are defined by open frames which support large glass slabs as the dominant upright panel structure, and wherein the sliding door is defined by a heavy glass slab which mounts a roller arrangement on the upper edge for horizontal rolling support along a guide track which is fixed to and extends horizontally lengthwise along the doorway and adjacent wall panel headers.
A full-height wall system of this latter type, namely a system wherein a sliding door is defined by a glass slab which is rollingly supported from a track which is fixed to and extends along the doorway header, is disclosed in co-pending application Ser. No. 11/450,908 (filed Jun. 9, 2006) as owned by the Assignee hereof. The disclosure of this latter application, in its entirety, is incorporated herein by reference.
While the wall system and specifically the sliding door arrangement disclosed in aforementioned application Ser. No. 11/450,908 is believed to provide a desirable solution with respect to both structural and aesthetic aspects associated with the design of a sliding door for a prefabricated upright wall system, particularly a system employing a glass panel door, nevertheless there still exists a need for an improved sliding door arrangement and specifically an improved doorway header capable of supporting a door arrangement defined by a double sliding door. More specifically, when one provides a double sliding door in a prefabricated full-height wall system, the width of the doorway or door opening is effectively doubled, that is a width of about eight feet in comparison to the typical four foot width associated with a typical single sliding door. The door header hence must have significantly increased length corresponding to the width of the double doorway and, since the doorway header is vertically supported solely at its ends, the increased length or span of the doorway header makes the header more susceptible to vertical deflection under load, absent substantial additional strengthening or stiffening of the header. In addition, the deflection associated with the long doorway header is further compounded by the fact that the header is subjected to a significantly greater load, namely the load imposed thereon due to the weight of two heavy glass doors when the doors are supported from the header and are positioned in direct sidewardly adjacent relationship so as to close off the double wide door opening. The substantial doubling of the length of the door header, coupled with the substantial doubling of the load imposed thereon by the double doors, hence significantly increases problems associated with structural design of the header and the resulting aesthetics thereof, while at the same time minimizing deflection of the header under load. In particular, such deflection can seriously impair or destroy the overall aesthetics, particularly when the two doors are in a closed position, since any significant downward deflection or bowing of the header causes the doors to swing or skew outwardly away from one another, thereby creating an irregular visible gap between adjacent side edges of the doors, particularly adjacent the lower extremities of the doors.
Accordingly, it is an object of this invention to provide an improved double sliding door arrangement for an upright wall system, which double sliding door arrangement provides significant improvements with respect to compensating for deflection of the doorway header so as to provide significantly improved aesthetics when the double doors are in a closed position, whereby adjacent opposed inner side edges of the double doors when in the closed position define a relatively uniform vertical reveal line or gap therebetween.
In the improved double sliding door arrangement of the present invention, the door header is provided with a reinforced header beam which is pre-stressed to have a slight upward deflection or bow when in a non-loaded condition, that is, when the doors are in an open position and supported on segments of the roller track which are supported on the wall panels disposed on opposite sides of the doorway. When the doors are moved into the closed position and impose their weight load on the roller track carried on the doorway header, however, the pre-stressed header beam is deflected downwardly. This load-induced deflection initially overcomes the upward pre-stressed deflection so that the beam initially moves into a straight condition, with the load causing the beam to continue deflecting downwardly into a downwardly bowed configuration. The overall downward deflection of the doorway header beam due to loading thereof by the double sliding glass doors is generally of a magnitude such that the beam deflects downwardly below a straight condition by a magnitude no greater than the pre-stressed upward deflection above the straight condition. The downward bowing from the straight condition under a fully loaded condition is hence minimized to a sufficiently small magnitude so that the sidewardly-adjacent closed doors do not experience less outward swinging away from one another, thereby preserving desired aesthetics with respect to the opposed adjacent vertical side edges of the closed doors.
In the improved double sliding door arrangement of the present invention, as aforesaid, the overall door arrangement preferably includes roller support units mounted adjacent opposite upper corners of each door for rollingly supporting the door on the overhead support track. Each roller support unit preferably includes a vertical adjustment capability which enables its respective roller to have at least limited vertical positional adjustability relative to an upper edge of the door to improve aesthetics and to compensate for deflection of the doorway header beam under load. The two roller units on each door can be adjusted differently so that the rollers closest to the inner vertical edges of the doors are slightly lower. While this may cause the doors when in the open position to have a very small inward angled displacement toward one another, such angular displacement is not noticeable when the doors are widely spaced apart (i.e. in the open position) and are disposed in overlying relationship to the respective wall panels. As the doors move toward the closed position and effect loading and consequent downward deflection of the doorway header beam, however, this slight inward angular displacement of the doors due to the different positional adjustments in the door support rollers compensates for downward deflection of the door header beam below the straight condition, since this latter downward deflection tends to angularly swing the pair of doors outwardly away from one another so as to position the opposed inner upright edges of the two doors, when in the closed position, directly adjacent one another in substantially parallel relationship to thereby provide an improved and pleasing aesthetics.
Other objects and purposes of the invention will be apparent to persons familiar with constructions of this general type upon reading the following specification and inspecting the accompanying drawings.
Certain terminology will be used in the following description for convenience and reference only, and will not be limiting. For example, the words “upwardly”, “downwardly”, “rightwardly” and “leftwardly” will refer to directions in the drawings to which reference is made. The words “upwardly” and “downwardly” will also be used in their conventional sense to indicate the orientation of the wall structure and door assembly relative to the floor and ceiling with which they are associated. The words “front” or “outer” will be used to reference the exposed side of the door which is always visible, irrespective of whether the door is in its open or closed position, and the words “back” or “inner” will be used to refer to the side of the door assembly which directly confronts and overlaps the wall when the door is in an opened position. The words “inwardly” and “outwardly” will refer to directions toward and away from, respectively, the geometric center of any referenced assembly or any referenced part thereof. Said terminology will include the words specifically mentioned, derivatives thereof, and words of similar import.